No car is more versatile than the Austin Seven in the matter of interchangeability of parts, and for this reason it is a popular basis for amateur conversion and “special”-building. Now that economy motoring must be foremost in the minds of many, this famous little car will obviously continue to be the subject of enthusiastic modification. Much could be written on what to do and what not to do, but there is no better guide than studying what has actually been done in the past. So we publish below the condensed specifications of some interesting non-standard Austin Sevens, by kind permission of the 750 Club, from back issues of whose Bulletin the data has been extracted. The performance claims are the owners’ own, and seem optimistic in some cases, but no doubt all these cars went very well. We have confined these descriptions to unsupercharged cars used on the road, as being of the greatest interest to impecunious would-be Austin advocates.
P. R. Quiggin’s 2-seater. – 1926 fabric 2-seater, less axles, and 1929 “Swallow.” Front axle dropped as “Ulster” by bending and welding-in a distance piece. Front spring main leaf reset with centre below shackles and remaining leaves fitted upside down. Spring taped and bound. Radiator cap now 31 in. from ground. Magneto-type engine with double valve springs, Bosch magneto and Alta head. Fitted with new main bearings. Steering column well raked, and extended, and 18-in, wheel fitted. Ten-gallon Rover fuel tank above back axle, giving a mere 4-in, head of fuel (Autovac later). Two-seater body formed from remains of “Swallow” saloon. One aero screen. 4.9-to-1 axle. 4.00-in. by 19-in. tyres. Three-speed box. Weight with 3 gallons fuel, 7 cwt. exactly. Claimed to cruise at 45 m.p.h. and to have put 42 miles in 1 hr. 0.5 min. Very sure starter. Cornering excellent, but a bit of a handful on the straight.
P. H. Hunter’s A .E. W. 4-seater. — A 1934 car purchased from H. B. Shaw in 1939. Clutch relined and five new Dunlop “Freighter” tyres fitted. Ran in C.S.M.A. winter trial, registering one failure, to gain 2nd class award. Light front wings made from a motor-cycle mudguard, cut in half. Engine dismantled and carefully reassembled, but standard except for double valve springs and a Klingert h.c. gasket. Ran in C.S.M.A. Championship Trial and lost no marks, being second to King’s 328 B.M.W.-engined Frazer-Nash in acceleration test. Clean sheet in 750 Club Committee Cup Trial. Plug trouble in General Aircraft M.C. Night Trial. Performance claimed: 45 in 3rd and 68 in top gear, and 80 miles covered in 2 hr. min. 6 sec. on good road. Used Discol. Later fitted Invur-strut split-skirt pistons, Zenith downdraught carburetter, “Nippy” inlet manifold, and “Ulster” exhaust manifold. Thereafter suffered from fuel starvation, as mechanical pump could not cope. Sold to Birkett, who eventually sold her back to Hunter.
H. Birkett’s “Ulster.” — Probably a T.T. Replica. First registered 1934. Bought in unblown state, with updraught Solex carburetter, l.c. Alta head and 4.9-to-1 axle. Stripped rear axle pinion and then rebuilt. Engine kept as it was, using the 1 1/8-in. diameter-pressure-fed crankshaft. Axle replaced by 5.25-to-1 type, which added 15 m.p.h. Large diameter exhaust pipe carried under rear axle and given a 12-in. fan-tail. Spare wheel moved from tail to offside of body and Smith’s headlamps fitted. Used for Continental tour, cruising at around 60 m.p.h. Crankshaft period at 2,500 r.p.m., or 40 m.p.h. in top gear. Gradients of 1 in 10 suited 2nd gear of the close-ratio box. The car was later rebuilt, with boxed-in frame, transverse rear Hartfords to cure tail-end float, and raised steering box to further rake the column. The minor controls were scrapped to permit a flexible wheel, the exhaust system was carried above the rear mudguard and 17-in. wheels replaced the former 19-in. ones. The old crankshaft was retained, but an alloy head was fitted, giving about a 7.5 to 1 compression ratio. On a round-the-British Isles tour the crankshaft broke, so a standard engine was installed, much over-geared. Magneto trouble was soon experienced. Later a special engine was installed, with a 1 1/2in. diameter, Laystall, two-piece, dynamically balanced crankshaft, a Scintilla P.N.4 magneto and a 1 1/4-in. downdraught S.U. carburetter on a “Nippy” inlet manifold. The Smith headlamps were replaced by Zeiss, and the “Ulster” went abroad again. It now cruised happily at 4,000 – 4,250 r.p.m. = 67 m.p.h. During the. war the car was given a Ford Eight carburetter in place of the S.U., and did a daily 25-mile journey, and also pulled a trailer. It was later dismantled and the engine used in a 3-wheeled “special,” and now in Birkett’s Ruby-chassis 2-seater “special.”
J. S. French’s 2-seater. – 1929 coachbuilt saloon-chassis and home-built body based on a 1926 “Brooklands” Austin. Chassis dropped 7 1/2 in. at the back and 5 1/2 in. at the front. Standard small-crank engine thoroughly overhauled, with polished combustion chambers, h.c. gasket, enlarged ports, polished and flaired inlet valve guides, double valve springs and no fan. Every other clutch spring double to avoid slip. 4.9 axle. 4.00-in. by 19-in. tyres. Propeller-shaft period at about 38 m.p.h. and some vibration flat out. Performance claimed: over 40 in 2nd and 70 m.p.h. in top, with cruising speed of 50 m.p.h. Oil consumption nil; fuel 47 – 48 m.p.g. on long run, with standard FZ Zenith carburetter with comp. jet reamed out slightly. Body of sheet steel and 20-gauge aluminium. Staggered seats, battery under floor, spare wheel in tail, ground clearance 4 1/2-in.
E. G. Smith’s Trials “Special.” — Initial experience gained with a magneto ignition 1928 Gordon England “Cup” 2-seater bought in 1933. With lightened flywheel, double valve springs, and Ricardo alloy head it ran in many trials, climbing Nailsworth Ladder, driver only up. Very reliable, and cruised at 40-50 m.p.h. Replaced by 1931 2-seater, which climbed Beggars Roost, minus passenger. New car built, using engine from “Cup” 2-seater. Ariel car 3-speed box bought for 10s. and fitted behind standard 3-speed box. Chassis extensions made from Morris and Vale chassis members, and strong body from 1927 “special” Austin fitted to resist efforts of 14-stone passenger. Wide front axle, with springs half-way between standard and “Ulster.” 4.50-in. by 17-in, competition rear tyres. Ran in several trials, but ratios too wide and engine lacked just the little bit of urge required. 1930 “Ulster” engine and close-ratio box substituted for standard unit. Home-made divided front axle used, to give i.f.s. Most trials hills taken in bottom on Ariel box and top on “Ulster” box, with quick change in 2nd on latter box. “Bottom/bottom” sometimes needed, but not for Red Roads. Rapid tyre wear resulted in i.f.s. being replaced by home-made axle of “Ulster” type. Car now climbed Simms, Fingle Bridge, Doverhay, Ham Hill, Breakheart, Cussop-Dingle, and many others. Widlake and a few Kentish chalk bills defeated it. Engine kept as near to 4,000 r.p.m. as possible on trials ascents. Crankshaft eventually broke, but engine rebuilt with standard crankcase and crankshaft, using “Ulster” camshaft, but was prone to lose big-ends. Car next converted in 3-wheeled “Ulster Barrow,” using James, Raleigh, Vauxhall and Riley parts, to enable it to run in motor-cycle events, while being easily converted back to fourwheeled form. Front-Wheel wobble finally overcome and a Premier Award won in the M.C.C. London-Exeter trial. Van engine fitted and car sold when war came.